The present invention relates to a device for supporting, in a manner capable of being displaced, an optical fiber bundle for use in transferring a light beam. More particularly, the invention relates to a device used in an image scanning and recording system for photoelectrically scanning an original image to produce image signals, and the recording said image on a recording sheet material having a photosensitive agent thereon.
Generally, optical fibers are used for transferring light from a light source to any desired place by simulating bending of light through the use of multiple reflections of light caused in the interior of the optical fibers.
Reference is now made to FIG. 1 of the accompanying drawings showing that when a condenser lens plane 1 is irradiated with light from an optical fiber bundle, a speckled pattern having light and dark areas can be seen, as shown in FIG. 1, instead of a uniform distribution of light. If the entire region of light indicated by a circle B in FIG. 1 is used, the total light quantity will not change. However, if the distance between the irradiated condenser lens plane 1 and the outlet end of the optical fiber bundle is increased, the circle B becomes enlarged, so that a larger system is needed in order to make use of all of the enlarged light beam. As a result, generally only the circle A which is the central area of emitted light is used in the optical system.
In cases where a portion of the light emitted from the optical fiber bundle is used in this manner, changes in the speckled pattern are caused by the movement of the optical fiber bundle; more specifically, because of the nonuniformity of the distribution of the light, changes are produced in the total light within the circle A of the central area of light. For example, if this light beam is used in an image scanning and recording system, the movement of the optical fiber bundle in the subcoordinate scanning directions results in unevenness of an image formed by spots of light, thereby failing to provide an accurate record.
The cause of this problem will now be investigated. The construction of a unit optical fiber F is shown in FIG. 2. The fiber F is formed of a core 2 and a clad 3, and the light beam travels in a light path 4 as shown in FIG. 2b; the light beam travels in the core 2 while reflecting internally off the clad 3. As a result, if the optical fiber F produces a displacement such as by bending, the optical path 4 changes, and so, the distribution of quantity of light emitted from each optical fiber and impinging the condenser lens plane 1 and hence the quantity of light in the circle A will also change.
Thus, where the optical fiber F is used in its absolutely fixed position, no change in the speckled pattern is caused. However, when it is moved is always a change in speckled pattern.
An examination of such changes in the case of bending as one condition of movement of the optical fiber bundle reveals that, as shown in FIG. 3a, corresponding to FIG. 1, a change in the light path 4 is produced, with the speckled pattern in the circle A changing such that it is shifted in and out of the circle A, as indicated by arrows 5, and so, the light quantity in the circle A changes with the bending displacement.
In contrast, where the optical fiber bundle is twisted, as shown in FIG. 3b corresponding to FIG. 1, it has been found that where no bending force acts on the optical fiber bundle, there is no change in speckled pattern in the circle A like the change shown in FIG. 3a; i.e., in the circle A the speckled pattern changes only in the direction of twist (direction of rotation) as indicated by arrow 6, which means that the light quantity in the circle A changes minimally.